The invention relates to a method and an apparatus for the stacking of rectangular products, particularly printed matter such as books, book blocks or magazines, whereby the products are collected to form a row of packed material, and the row of packed material is subsequently pushed onto a plate and is then swept from the plate. The invention serves particularly in the loading of pallets with rectangular products.
The German reference DE-OS No. 2,334,651 teaches an apparatus for loading pallets with piece material, in which the piece material is transferred by means of transfer devices onto individual pallets which can be raised and lowered by means of a stroke device. First, a stack of packed material arranged on the pallet is assembled on a conveyor belt having a stop plate at the back side thereof, which is then pushed altogether onto a packing plate by means of a slider. The packing plate can move parallel to the direction of movement of the conveyor belt. The packing plate is located above the pallet, and the stop plate extends beyond the packing plate. The plate is removed, and as it is withdrawn the packed stack is swept off, so that the packed stack ends up on the pallet or on a previously deposited packed stack. This apparatus operates slowly, because the formation of the stacks cannot take place until the slider has been retracted. In addition, the entire system requires a great deal of space.
The German reference DE-OS No. 2,160,555 describes an apparatus for forming a stack from rectangular packed elements on a lowerable stacking table with the use of a horizontal reciprocating collecting plate, from which the packed items are placed onto the stacking table in layers. The packed items arrive at a right angle to the direction of movement of the collecting plate sequentially on a stationary feed table and form a row. The row is pushed off onto a lower collecting plate by a reciprocating sweep until a layer of packed items is formed. The collecting plate then moves to a position above the stacking table and back into its original position, whereby the layer of packed items is swept off by means of a block which can be pivoted into place to do so. The layer of packed items is then deposited on the stacking table or on the previously deposited layer. Even this known apparatus operates too slowly, because the supply table cannot be reloaded until the sweep has reached its original position. The space required is also significant, because the collecting plate must transport the layer of packed items to the stacking table.
A very rapidly operating method of forming a stack of books on a pallet is described in the German reference DE-OS No. 27 18 338. A row of packed goods is formed on a conveyor belt and the row is pushed laterally to the conveyance direction of the conveyor belt onto a packing plate by a sweep. Because the sweep can move upward after sweeping off the row and then moves back and down into the original position and does not merely reciprocate, the transport belt can be loaded during this motion. The depositing of a layer occurs by retracting the packing plate located above the plate, parallel to the conveyance direction of the convyor belt, and simultaneously sweeping off the layer of packed items. This known device requires a great deal of space, because the movement of the packing plate requires a great deal of space.